The present invention relates to a system for detecting movement of a belt in an associated drive system.
In the past a variety of devices have been used to detect belt slippage or belt failure in a drive system. As an example, forced air heating/cooling systems generally employ an air flow switch in the return duct to detect whether or not air is moving through the system. One problem with such an arrangement is that the air flow switch sensing vane can become coated with airborne dirt, rendering it inoperative. As another example, pressure sensing switches are used in liquid pumping systems to detect whether or not the system is operating. Should such pressure switch fail hydrostatically, the liquid can enter the electrical portion of the switch, rendering it inoperative. What is desired is a means for detecting slippage or failure of a drive belt in a belt drive system.
U.S. Pat. No. 3,877,003, issued Apr. 8, 1975 to Kawashima describes a warning system for belt slippage wherein the rotational speed of a driven member is compared with the rotational speed of a driving member, and a warning is given when the output signal of the comparing means reaches a pre-determined value in a driving system wherein the driving speed is not constant, as in an automobile engine. However, a simpler detecting arrangement is desired for a system wherein the driving speed is constant.
Accordingly, it is an object of the present invention to provide a system for detecting movement of a belt in a belt drive system.
Other objects, aspects, and advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the invention, the attached drawing and the appended claims.